Pneumatic separator



Feb. 17, 1931. w. M. BARKER 1,792,962

PNEUMATI G SEPARATOR Filed April 20, 1926 2.Sheets-Sheet l gwuehtoi am my Feb. 17, 1931. w. M. BARKER 1,792,962

PNEUMATI C S EPARATOR Filed April .20, 1926 2 Sheets-Sheet 2 gwuwtoo WMBar/Zer Patented Feb. 17, 1931 PATENT OFFICE-i WILLIAM" BARKER, or cannon, onto 5 PNEUMATIC SEPARATOR Application net April 2o,

with, and to return the over-sized material back to the ing.

Such screens grinding machines for regrindhave been found to be very troublesome in plant operation. Theyblind' and clog and the screen wires break, making them uncertain in action, so that they require constant watching and attention,

To overcome the various difhculties with screens, many different kinds and shapes of mechanically operated screening devices have 7 been designed, but'such mechanically operated screening devices have not eliminated the imperfections inherent in screens in general for fine sizing or separating of dry or partially dry material.

It is generally the object of users of such devices to constantly increase the tonnage of material of a desired constant fineness which is processed through the separators intheir plants.

Screens in general, however, have been found so ineffective that it is quite common experience to find that to 7 5% of material, that is already fine enough and should pass through thescreens ready for the next step in the manufacturing process being undertaken, actually passes over the screens as oversize and is returned to the grinding machines for regrinding. V

This constant recirculation of material actually fine enough for use, causes an extra and large circulating load to pass through the grinders and elevators, and necessitates an. extra consumption of power to operate the grinders and elevators as well as the separators.

Moreover,-fines that are returned to the completely separate material of any desired hereof in which 1926 Serial No. 103,281.

grinders due to the ineffectiveness of screening devices, cushion and retard the grinding action of the grinders on coarse material.

The objects of the present invention are-to fineness from a stream'of material as discharged from a grinding machine as'by the use of an elevator; and these objects are attained by subjecting ajpreferably vertically falling stream of material as discharged from the top or head of an elevator-to a preferably horizontal cross current as of air which, depending upon its pressure, carries material of a certain fineness with it and per mits coarser material to drop as into the intake of a grinding machine for further grinding and reduction in size.

Further objects of the invention are to provide a device which is simple and compact in construction and is provided with ample clearance at all points for undersized or unseparated material to drop freely bygravity down through a separating box, and so arranged that even damp material will not build up and clog the device.

A preferred form of apparatus for attaining these and other objects by the means set forth aforesaid in general terms, is illustrated. in the accompanying drawings forming part Figure 1 is an elevationalview of a preferred apparatus embodying the invention, portions of the outer case walls being broken away to more clearly illustrate the interior construction of the device; and 35 Fig. 2, a vertical cross section thereof, as on line 22, Fig. 1. i

Similar numerals refer to similar parts throughout the drawings.

The improved pneumatic separator indicated generally at 10, includes walls forming a separating chamberll, and a separator inlet 12 including an upper inclined duct 12a communicating with a lower and preferably vertically directed baffle chamber 126 which communicates as at the junction 12?) with the separating chamber 11.

The separating chamber preferably includes upper inclined walls 11a and 11b inclining downward and flaring outward from their connection with the baffle chamber 12?), a lower inclined and angled wall 110 having the general inclination of the wall Ila and including an upper section 110 of one slope and a lower section 110 of a greater slope, a preferably vertical wall 11d laterally offset a substantial distance from the axis of the baffle chamber 121), which distance is preferably greater than the width 10 of the baffle chamber, together with end walls 116 and 116. l l

The wall 116 and the upper portion 110 of the angled wall 110, converge to communicate with an inclined outlet 13 for separated material or fines of a proper size, and the lower portion 110' of the angle wall 110 converge to communicate with a preferably vertically directed outlet 14: for discharging oversize material as to the inlet of a grinding machine. The outlet 1% is preferably laterally offset a substantial distance from the inlet halite chamber 126, for purposes hereinafter to be described in detail.

The separator inlet 12 communicates with a preferably downward depending outlet at the top or head of an elevator case 16 in which is operatively mounted an elevator as a bucket elevator 17, which lifts unseparated material M which may be discharged from a grinding machine, to the elevator head or top at 18, and delivers said unseparated material into the separator inlet 12 through the outlet 15.

The separator inlet 12 as aforesaid may preferably include a duct 12a inclining down ward and flaring outward from its connection as at 19 with the elevator case outlet 15, and the duct 12a communicates with the prefcrably vertically directed balfle chamber 12?) provided with a plurality of spaces and op positely inclined b file platforms 20 and 20 for evenly s1 1 ing out material par-sing through the separator inlet into a thin, wide, vertically falling stream. 7

Opposite the outlet 13, the separating than! her is provided with a plurality of substantially horizontal nozzles 21a, 21?; and 21c extending preferably across the whole widt of the separating chamber, the nozzle outlets being preferably stopped with each otl .r, that is to say, the nozzle 21?) extends into the separating chamber beyond the nozzle 21a, and the nozzle 210 extends into the separatiu chamber beyon d the nozzle 21?).

The nozzle 21a is preferably in the form of a relatively narrow horizontal slot in the wall 11d, adjacent the junction of the inclined wall 11a and the wall 11d, and the o thus located a substantial distant to one side of the junction 12?) of the vortically directed bafile chamber 12?) and the separating chamber 11.

For deflecting upwards a current of air entering the chamber 11 through the upper nozzle 21a, a preferably horizontal deflector plate Pl extends from the lower edge of the nozzle 21a into the chamber 11 to a junction as at J 1, with a preferably vertically extending plate P2 preferably in line with the wall 125 of the baffle chamber 126, next adjacent the wall 11d of the separating chamber.

The nozzle 21?) is preferably formed by a horizontal slot in the wall 116 spaced below the nozzle 21a, and communicating with preferably horizontal upper and lower plates P3 and Pa extending into the chamber 11 beyond the vertical wall P2, and to the end J2 of nozzle 21b, and the lower plate Pet making a junction at J2 with a preferably vertically extending plate P5;

The nozzle 210 is preferably formed by a horizontal slot spaced below the slot for the nozzle 21 o in the wall 115, and communicating with preferably horizontal plates P6 and PT extending into the chamber 11 beyond the wall P5, to the end 53 of the nozzle 210.

The vertical plate P2 preferably extends to connect with the upper horizontal plate P3 of the nozzle 21]) and the plate P5 preferably extends to connect with the upper plate P6 of the nozzle 21c, and the junction J1 and the ends J2 and J3 of the nozzles 21b and 210 are preferably substantially located in a plane making an angle of substantially sixty de grees with the plate P7.

The lower plate 110 of the separating chamberll is angled as at 110' below the outer end J3 of the nozzle 210 to form the aforesaid upper portion 110 of one slope and the portion 110" of a greater slope for reasons hereinafter to be set forth.

The nozzles 21a, 21?) and 210 communicate with the outlet 22 of a blower 24, which is suitably mounted and connected with a motor, not shown.

The separating chamber may be provided with an internal adjustable gate 25 preferably horizontally hinged at the top of the chamber as at 26 and provided with an outwardly extending bolt 27 passing through the forward upper inclined wall 28 of the chamber, upon which is screwed the adj ustable wing nut 29 for varying the area of the communication between the chamber 11 and the outlet 10 for the material or fines F separated from the material M to the proper size by the action of the device. The over-size material 0 from which the fines F have been separated by the action of the device, pass down through the outlet 1% as aforesaid.

The operation of the device consists essentially of dropping mixed material M, containing fines F of a desired size and over-sizc material 0, through the duct 12a of the inlet orifice 12 into the baflie chamber 12?) where it is evenly spread out into a thin, wide, vertically falling stream which passes in front of the substantially horizontal nozzles 21a, 21?) and 210.

The blower 24 being in operation, relatively thin horizontal blasts of air are directed into the separating chamber 11 as cross currents passing through the vertically falling stream of unsized material M.

The nozzle and having its end located in V the wall 11d, laterally offset a substantially distance from the junction 12?) of the baffle" chamber 126 with the separatingchamber 11, directs an upper blastof. air into the separating chamber which is deflected upwards byv the deflector plate P1 for first winnowing or fluifingthe verticallyfallingmaterial M, which is-next subject to the substantially horizontally directed blast issuing from the rend J2 of the nozzle 21?), located substantially directly under .the vertically directed battle chamber 126, and it has been found that the blast from the nozzle 21b operating upon the material M fluffed by the upwardly deflected blast from the nozzle 21a, performs a major portion of the actual separating action of the device.

For completely accomplishing the desired separation, the streamof material is next 5 subject to the substantially horizontally directed blast issuing from the end J3 of the nozzle 210,1ocate-d inthe chamber 11 as aforesaichbeyond the ends of the upper nozzles 21a and 21b, andthe junction J1 and thc ends J2 and J3 of the nozzles 21?) and 210 being as aforesaid preferably located sub.- stantially in a plane making an angle of substantially sixty degrees with the plate It will be seen that as the respective air blasts leave their restricted nozzle chambers and enter into the relatively large separation chamber 11,said air blast-s will become suddenly expanded, thereby increasing their effective area upon the stream of falling material. It is therefore necessary to maintain a substantially constant distance between the nozzle outlets and the material stream in order to obtain the required effectlve pressure in each air blast upon the material stream. This isaccomplished by locating the nozzle outlets in stepped relation with each other, as above described.

The falling stream then impinges upon the upper portion 110' of the angle plate 110,

and the slope of the portion 11c is. preferably relativelygradual. so that the material falling upon it will slide thereover with a relatively slow speed, in order that the full effect of the blast from the nozzleJB may be attained for completely separating the fine material F from the oversize material 0.

After the oversize material 0 has slid over the junction 110 of the angle plate 110 upon the relatively steeper lower portion 110', the vertical velocity of the oversize material is increased with reference to the velocity of the material slidingover the upper portion 110, thereby enabling a rapid removal of the oversizejonce it has been separated from the fine by the action of the threesteppe'd blasts The oversize material 0 slides over the relatively steep portion 110 of thevlower angle plate 110 into the oversize outlet 14, which maybe connected with a grinder in let for regrindi-ng theoversize.

By the arrangement of'the plates P6 and P7 extending into the chamber 11 over the oversize outlet 14 to their end J 3 substantially above the junction 110", of, the angle plate 110, and by thelateral. offsetting of the oversizeoutlet 14 from the inlet 18, and

The size of the fines F recovered from the falling unsized material M, depends. solely upon the pressure of the cross current air.

In tests made with apparatus embodying theinvention as aforesaid, it has been found that only a slight pressure of cross current air is required to be delivered by the blower through the horizontal nozzles, because this air does not have to lift or divert the whole of the material M as delivered from the ele-v vator, since the heavy over-size 0 drops by gravlty past the air nozzles and is unaffected by the cross currents. The cross current air delivered from the separating nozzles is used only to divert into the fine outlet 13 the material that is of the predetermined fineness as fixed by the pressure of the currents.

When the air jet pressure is determined by trial for separating fines F of a given size, from unsized material M, and the regulation of the blower and the adj ustinent of the gate have been made and set, this separating pressure is delivered through the nozzles continuously and on more attention is required for the apparatus excepting to maintain the cross current air pressure con-.

stant by suitable regulation of motor, or otherwise. Should another size of fine be desired at any time, it may be readily obtained by merely changing the blower fan speed, or by throttling the flow of air by means of a suitable gate on thefan intake, or in the delivery pipe from the fan to the nozzles.

the blower It has been determined by experience with operations of the apparatus that an air pressure of inch watergauge is amply sutiicient to separate 1 inch material such as shale, clay, and limestone, from a falling til stream of unsized material; and for fines of a size of minus 12 mesh, good results may be obtained with as low a pressure as inch water gauge.

The low air pressures required by the device for operation, necessitates the use of power materially less than that required to run usual types of mechanically operated screens.

It has also been determined that the apparatus provides a clean separation, and that in practice the lines going back with the oversize for regrinding is not more than 2%. This much less as aforesaid than the percentage of fines redelivered to the grinding machines by screening devices of equal capacity.

The apparatus will also handle material containing water, and so damp that it would at once clog up and coat over usual types of screen. The device will process without difficlllll) material as damp as it is desirable to run throu h ordinary dr )ans. Consequently by the use of the apparatus, clay and shale may be dampened at the pans to prevent dust rising and escaping from the grinders.

Since such a small quantity of separating air is required for operating the apparatus, the fines may be conducted from the separator direct through pipes to closed storage or feed bins, provided with vent pipes, without serious loss of dust.

Likewise, the entire plant may be rendered practically dustless, either (1) by running a pipe from the suction inlet to the fan into the top of the dryin rooms as of a brick plant. so that the moisture from these rooms ma be utilized in the apparatus, or a. steam or water spray may be arranged to set lo the dust in the receiving bins, or (3) water or steam vapor may be automatically ted .in at the suction inlet of the fan in sufficient quantity to dampen the material. being processed, so that no dust arises in the bins.

Each of the above methods of providing for dustless plant operation have been found to be practical. by actual OPGEHt-lOli of the device herein, arranged as aforesaid.

A further advantage of the present apparatus is its compact size, by which less plant space is required than is required for screens of canal c pacity, permitting the present device to be i ta d in part of the space now occupied by screening devices, and releasing floor space for otl or uses.

In the construction of new plants, plant lav-out and the plant flow sheet may be me.- terially simplified and improved by the use f the present apparatus. enabling the elimination of conveyors, and the attainment of a substantially dustless plant.

In addition to the foregoing uses, the device is adapt-ed for cleaning coal from a mix ture of coal and slate. That is to say the mixture M may consist of coal F and slate O. and the coal F may be removed from mixture as heretofore described.

I claim 1. The method of separating unsized material into line material and oversize material,

which includes subjecting a single stream of freely falling unsized material to successive suddenly expanding currents of fluid such as air for diverting the line material from the stream to another stream, each successive current of lluid suddenly expanding at a position horizontally offset from the position of sudden expansion of the preceding current to compensate for the horizontal displacement of the material stream due to the elfect of the preceding current. I

2 The method of separating unsized material into line material and oversize material, which includes subjecting a single stream of freely failing unsized material to successive suddenly expanding currents of fluid such as air of equal pressure for diverting the fine material from the stream to another stream, each successive current of fluid suddenly expanding at a position horizontally ofl'set from the position of sudden expansion of the preceding current to compensate for the horizontal displacement of the material stream due to the effect of the preceding current.

3. The method of separating unsized material into line material and oversize material, which includes subjecting a single stream of freely falling unsized material to successive suddenly expanding currents of fluid such as air in a single chamber for diverting the fine material from the stream to another stream, each successive current of fluid suddenly expaneling at a position horizontally offset from the position of'sudden expansion of the preceding current to compensate for the horizontal displacement of the material stream due to the effect of the preceding current.

4. Apparatus for separating unsized material into line material and oversize material, which includes means for creating a single stream of freely falling unsized material, walls forming a separating chamber in the path of the material stream, vertically spaced horizontally directed air nozzles communicating with said chamber, the successive nozzles being horizontally offset for maintaining a substantially constant distance between the material stream and each nozzle, and means for supplying a current of air to each nozzle.

5. Apparatus for separating unsized ma.- terial into fine material and oversize material,

which includes means for creating a single stream of freely falling unsized material, walls forming a separating chamber in the path of the material stream, vertically spaced horizontally directed air nozzles communicating with said chamber, the successive noz- .Llifl zles being horizontally offset for maintaining a substantially constant distance between the material stream and each nozzle, means for supplying a current of air to each nozzle, and an outlet for the fine material substantially horizontally opposite the air nozzles. i

In testimony that I claim the above, I have hereunto subscribed my name.

WILLIAM M. BARKER. 

